Diabetes is a chronic disease symptomized by high blood glucose due to impaired insulin secretion or impaired insulin action. Over 90% of diabetes is type 2 diabetes, which is categorized as a lifestyle disease, and is most often accompanied by abnormal lipid metabolism (like obesity or hyperlipidemia). The pathophysiology of diabetes such as hyperinsulinemia is a vicious cycle in which the release of VLDL and the synthesis of triglycerides in the liver is accelerated, hyperlipidemia worsens, and an increase in triglycerides or free fatty acids caused by abnormal lipid metabolism further compromises insulin action. Consequently, hypoglycemic drugs and antilipemic drugs are often taken together.
Drugs that work to lower triglyceride levels include nicotinic acid drugs and fibrate-based drugs. It is known, however, that nicotinic acid lowers glucose tolerance, and as for fibrate drugs, while Bezafibrate does improve insulin resistance and thereby strengthens the hypoglycemic action of concurrently used drugs such as sulfonylurea-based drugs, it does not itself exhibit any hypoglycemic action.
Compounds that have a hypoglycemic action include sulfonylurea-based drugs, thiazolidine derivatives, biguanide, α-glucosidase inhibitors, and so on, but other than thiazolidine derivatives don't acts on lipids.
It is stated in the Patent Document 1 that a 4,5-dihydronaphtho[1,2-b]thiophene derivative that is a compound whose structure is similar to that of the compound of the present invention is effective-in the treatment of respiratory disorders, immunoregulation, the treatment of acute tumor diseases, antiedema treatment, the treatment of venous disorders, and so on. However, the compound of the present invention is not mentioned, nor is there any mention of the action of lowering triglyceride levels in the liver or the action of lowering blood glucose levels.
Patent Document 1: Japanese Laid-Open Patent Application No. S61-194081